Flutter升级后无法运行代码，Gradle依赖下载超时求助

问题描述 #

我在完成Flutter升级操作后，完全无法运行任何代码——就连官方示例项目启动时都会抛出异常。我已经尝试搜索相关解决方案，但都没能解决问题。构建过程中出现的核心异常如下：

FAILURE: Build failed with an exception.
* What went wrong:
Could not determine the dependencies of task ':app:compileDebugJavaWithJavac'.
> Could not resolve all task dependencies for configuration ':app:debugCompileClasspath'.
> Could not resolve io.flutter:flutter_embedding_debug:1.0.0-9d5b21729ff53dbf8eadd8bc97e0e30d77abec95.
Required by:
project :app
> Could not resolve io.flutter:flutter_embedding_debug:1.0.0-9d5b21729ff53dbf8eadd8bc97e0e30d77abec95.
> Could not get resource 'https://dl.google.com/dl/android/maven2/io/flutter/flutter_embedding_debug/1.0.0-9d5b21729ff53dbf8eadd8bc97e0e30d77abec95/flutter_embedding_debug-1.0.0-9d5b21729ff53dbf8eadd8bc97e0e30d77abec95.pom'.
> Could not GET 'https://dl.google.com/dl/android/maven2/io/flutter/flutter_embedding_debug/1.0.0-9d5b21729ff53dbf8eadd8bc97e0e30d77abec95/flutter_embedding_debug-1.0.0-9d5b21729ff53dbf8eadd8bc97e0e30d77abec95.pom'.
> Connect to mirror.vtwo.org:8850 [mirror.vtwo.org/5.152.221.178] failed: Connection timed out: connect

后续x86_debug、x86_64_debug等多个Flutter依赖包都出现了相同的连接mirror.vtwo.org:8850超时问题，最终导致Gradle的assembleDebug任务失败，退出码为1。

我的flutter doctor检测结果显示一切正常：

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 1.20.2, on Microsoft Windows [Version 10.0.18362.1016], locale en-US)
[√] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
[√] Android Studio (version 3.5)
[√] VS Code (version 1.47.2)
[√] Connected device (1 available)
• No issues found!

解决方案 #

更新： 我尝试升级了项目中的Gradle版本后，问题成功解决了。

内容的提问来源于stack exchange，提问作者Wehid Behrami